I did still have to carve places for a few of them...

The explobox outside (by the 2 pipes up the rock face, with the one key behind, and another key on top for hard) was placed with speedrunning in mind, so that those with enough health (and a corresponding lack of common sense) can box jump over. Like I said in #12, I did intend that jumping on it then onto the pipe was also possible, although without coding changes (details, please), it only works in DP. I'm fairly sure that you can also get over with an OGJ or an enforcer boost - height to get on top of the thin clip brush is 48, or onto the diagonal pipe is 56 (I think) - but I didn't test it.

And as for having two kinds of keys -- one for progress, one for optional "stuff", should I show you as also voting for keys and coins? 

Prince of Persia 4 (sands of time) had rooms full of bad guys, but after killing them, you had to discover what acrobatic tricks / combination of lever-pulls you needed to use to continue, which required studying the room. This also had a side effect that you pretty much need to fight the monsters to continue, becuase you can't stand still long enough to solve the puzzle if you have monsters attacking you.

Same principle in Tomb Raider. The slow progress there is a bit extreme though. In Quake, you could run through most TR maps in 30 seconds (provided you survive the traps).

It comes down to lots of keys (and semi-hidden buttons), with trap gauntlets and puzzles thrown in that are non-optional. Some ladders and underwater currents are also not obvious, so you need to look closely. You'll often have to change the environment to proceed. Extend something you can climb on; raise and lower the water to get at levers/entrances; activate currents to make a long swim without drowning. Push blocks around to climb on or find a button, or to clear a path to a timed door.

The effect of actually deadly traps and realistic fall damage (in combination with bigger levels, deep chasms etc) is that you'll mostly want to Always Walk, instead of Always Run as in Quake. I have a finger on the Walk key almost constantly in TR.

It's only "key keys" in TR though, no "coin keys". A primitive "inventory ring" is used to manage the rather few objects you're carrying. Comparable to Hexen 2's inventory, but there simply aren't that many items. It's rudimentary, but works extremely well. If you have custom keys, it is very helpful to have this, although Lara will use the right key automatically on a lock, if she has it.

TR's secrets are typically plentiful and well-hidden; they contain primarily health and ammo, i.e. finding them makes the game easier. TR 2 takes secrets to the extreme; you'll only get items if you collect all three dragon statuettes in a level, i.e. you must find all secrets to get anything at all. The secrets are never mandatory though; since you don't get items ingame (in TR 2, the original game did give you items), they are purely a bonus, and reward exploration.

I'm surprised TR isn't more popular in this community. Is it because it is "for girls"? It did all those things, at the same time as Quake. Quake's gameplay seems very one-dimensional in comparison. id's engine is without a doubt better; but scope and vision, assets like transparent/moving water (including floating bodies), breakable glass, transparency, working rotation, semi-intelligent chasecam etc., and actual player model animations for swimming, jumping and climbing, and not least the level design, of the first couple TR games leave Quake and even Quake 2 in the dust. It's no contest.

The advantages of Quake are of a technical nature; a brilliant engine, customizability, and a set of working tools. The TR level editor seems to be... unpopular, and nothing is open source there.

The fact that we have discussions about more keys, traps and puzzles (and storytelling) at this point is kinda ironic.

IMO engines should start to include a simple inventory; there are working examples in Quake 2 and Hexen 2. Or else just give us a list when pressing Tab. 

I did still have to carve places for a few of them...

Sure, but the map had it's fair share of nooks and crannies and multiple levels and so on. Something like e1m2 would have been harder, I'd have thought.

Oh, respawning biosuits as in e4m1rmx would have been nice, but I'm sure someone said that already.

should I show you as also voting for keys and coins?

Yeah, I think so. Worth trying, anyway.