I can't imagine how you're getting something like a 1st ed game with all that, though I'd be curious to hear your details.
Here are the details.
Don’t confuse the way 4e was presented in a multitude of god-awful adventures with the way the mechanics actually work. As I said above, with the exception of the XP system, there is not a single mandatory mechanic in 4e that stands in the way of having a 1e play experience (unless your experience depends on rules nostalgia, of course).
The mechanic that drives every edition of D&D is that it is a game of attrition that requires players to manage scarce resources that are periodically replenished, usually daily. Most of the resources are identical in 4e, with the exception that health is more properly measured in healing surges than in hit points.
Lets start with the skill/ability check system. The core mechanic in 4e for every type of check including combat is: roll 1d20, add your modifiers, compare to a target number.
That 4e “rules heavy” approach replaces the following 1e “rules light” mechanics: different strength modifiers to hit and damage; roll low on a d6 to open doors, except when you roll low on a d8; roll low on percentile dice to bend bars/lift gates; wisdom bonus to certain types of saves; different dex modifiers for AC and missile discharge; roll low on a d6 and apply a dex modifier to determine surprise; roll low on percentile dice for eight different Thief skills, with six different dex modifiers, eight different racial modifiers, plus a number of armor modifiers I can’t remember; different con modifiers for fighters and non-fighters; roll low on percentile dice for system shock; roll low on percentile dice for resurrection survival; different cha modifiers for loyalty and reaction adjustment; assassination table; assassin spying table; chance for a sage to know something table; roll low on a d6 to detect secret doors; weapon speed factor; armor class “to hit” adjustment; loyalty of henchmen table (percentile based, with a couple of dozen modifiers); detection of invisibility table; listening at door table; encounter reaction table (percentile based); morale table; ranger tracking (percentile based); evasion of pursuit mechanics (percentile based, lots of modifiers); matrix for clerics affecting undead; psionic v. psionic combat table; psionic v. defenseless psionic table; psionic v. non-psionic table; saving throw tables; entirely different combat system for sieges; entirely different, percentile based system for weaponless combat, with different tables for grappling and pummeling; rolling under ability score with 1d20 or 3d6, depending on your preference; and rolling under or over an arbitrarily chosen number on an arbitrarily chosen die any time you need to determine something randomly and can’t figure out what ability score to apply. Have I missed anything?
My point is, rolling a die to determine success or failure is common to 1e and 4e, and the only difference between using a unified mechanic and using a few dozen subsystems is how any charts you have to look at.
Social skills are just reaction and loyalty checks. Perception checks replace the find traps mechanic, the find secret doors mechanic, and the surprise mechanic. Ability checks are in pretty much universal use now, whether you are rolling a d20, adding mods, and comparing to a target number; or rolling a d20 or 3d6 and trying to get under your ability score.
Let’s look at hit points and healing. In 1e the character loses hit points over the course of the day and if he runs out he dies (unless someone binds his wounds: DMG p. 82). However, he can use magic to recover hit points. In 4e the character loses healing surges over the course of the day and if he runs out he dies (no exceptions). There is no way other than rest to recover healing surges. In practice these mechanics provoke the same behaviour from players; when they get low, it is time to hole up somewhere and heal.
In 1e, after a fight the party takes 10 minutes to search the bodies, search the area, etc., bind wounds, and those who need to heal apply resources in the form of potions (a consumable resource) and spells (a daily resource) in order to do so. In 4e, after a fight the party takes 5 minutes to search the bodies, search the area, etc., and those who need to heal apply resources in the form of healing surges (a daily resource). In practice these mechanics provoke nearly the same behaviour from players.
In 1e, if a character drops to 0 hit points, he bleeds out until he hits -10 hit points, at which point he dies. Bleeding and death can therefore take up to 10 rounds, and can be prevented by binding his wounds or applying healing magic. In 4e, if a character drops to 0 hit points, he makes death saves until he fails three, at which point he dies. Death can therefore take as few as three rounds, but on average occurs in six rounds, and can be prevented by binding his wounds or applying healing magic. In practice the mechanics provoke identical behaviour.
At the end of the day in 4e you sleep and recover all of your healing surges. At the end of the day in 1e you sleep and, if you use no magic, recover only 1 hit point (with certain modifiers for constitution). So theoretically natural healing is slower. In practice, I have never found that to be the case. Healing spells are recovered daily, and can be purchased from clerics in town (and the characters get a lot more gold from adventuring in 1e). At worst the cleric spends a whole day casting healing spells. I see little practical difference.
(It’s also worth mentioning that diseases are more prevalent in 4e and often take several days to heal if you don’t have access to magic.)
Let’s talk about light. In 1e, torches (40’ radius) cost 1 cp and last an hour. Noone ever runs out of light. We were discussing it in this thread
and I don’t think anyone had ever run a campaign where someone ran out of light. Any risk is completely obviated by third level, when either the MU can cast continual light (60’ radius) on a stick, or you can pay a MU to cast continual light on a stick, always assuming you haven’t picked up a magical sword or dagger. By fifth level your cleric definitely has continual light (120’ radius). And pretty much all the demihumans in the party have infravision.
In 4e, torches (25’ radius) cost 1 sp and last an hour. Sunrods (100’ radius) cost 2 gp and last four hours. An everburning torch (25’ radius) costs 50 gp and lasts forever. (Note that characters can expect to get about 1/14th the amount of gold from adventuring between levels 1 and 2.) A light spell (20’ radius) costs nothing. As with 1e, there is not much chance of running out of light, but it is more expensive and it gives off considerably less light. And unless you have a drow, duergar, kobold, shade or svirfneblin in your party, nobody has infravision. And fewer parties include wizards.
If anything, light is more of a problem in 4e; but in most instances, the only difference in playstyle is that the 4e party will get surprised more, and the encounter distances are shorter.
Diplomacy checks, a charisma based mechanic, replace reaction tables, a charisma based mechanic.
There is no express mechanic for morale, but the skill system can accommodate it without making any new rules (Intimidate check, made whenever you would check in your favourite old school system). We found the 1e morale system clunky anyway, and tended to just roleplay NPC reactions based on their personality and the circumstances. I suspect using the 4e skill system for morale is more like Basic, if I am remembering it correctly, in that it is a simple roll against a target number.
Skill Challenges are a poor mechanic, but they are discretionary. I, and I think most people who still play 4e, generally use our discretion not to use them, which breaks no rules.
Character options can slow down character creation and level advancement. Fortunately, it can be done between sessions, so it has no effect on playstyle. It is also allowable to limit options. Lots of DMs limit options to just those in the PH, and there are actually fewer classes in the 4e PH than there are in the 1e PH. Others use the Essentials
books, which contain fewer classes with fewer options and simpler mechanics. And for those spur of the moment sessions, I keep a bunch of pregenerated first level characters around, and convert 1e modules on the fly.