I thought I'd play through the great amazing all-time favorite Oni in a day, so I started at around 17 and left the computer at just before 2. Had to save the last two levels for the next day, because everyone else was sleeping and I felt liked I'd wake them up at any moment (course I use headphones, but still, the computer is not completely quiet in a house with thin walls).
Point is I didn't finish the game in one day, though I easily completed it in less than 12 hours (a technical day). I'd like to say I didn't die once, but that would be a lie, I died plenty of times. In my defense I was playing the game on hard mode with a few mods installed to further harden the game (like how you get staggered when hit by bullets, making it impossible to move out of the way of certain weapon's rounds of fire). Usually I just run head on through some laser fields in zig-zac too, so the sentries won't have time to get me (which works fine even if I'm hit a few times along the way), but with this it doesn't work at all.
Also, I have a 'breakable glass / glass does damage' mod installed, so getting kicked through a window reduces life force by very much. I'm using the AE mod (a collection of mods) with all mods activated that add to the game without replacing anything (improved particle effects, rain splashes, breakable glass, new character textures, training level retexturized, some bug fixes, etcetc - but no completely new characters, new weapons, new levels that replace the old ones or such additions).
The only mod that does add to the realism that I didn't install is the improved enemy AI, allowing them to run as fast as the player, to dodge projectiles as easily as you do and to block much more often, a mod which I've played with before and which makes the game insanely hard to play through.
I'm not the stealth-kinda-person. I just want to run through the game, which is one of the reasons I love this game: because it's that kind of game. A fighting game. Fight with fists, kicks, weapons, hit switches, unlock doors, fight, pick up items, fight, unlock doors, fight! Sure there is some stealth involved; you don't want to run openly towards a sniper with a mercury-bow (kills you in four shots), or just rush straight into a cluster of enemies instead of fighting them two or three at a time, but it's pretty hands-on. It's not the easiest game around even without this mod, but it's one of those few games where you can polish your skills and where chance doesn't have such a large impact on whether you get killed or not.
The amount of moves and weapons is great and varied, the plot intense, the music fits the atmosphere perfectly and the levels are wide and futuristic. Some people think the levels are a bit too bland - not enough detail, but I think that's one of the things that makes this game stand out amongst any other similar games (though there aren't any similar games, this was the first one like this and so far I haven't been able to find anything more than remotely similar). The wide levels increase maneuverability, add focus on the fights, and they really aren't dull despite their size and lack of detail. They look good, they have the right amount of obstacles to make the game interesting without making it clustered. Nothing is ever in the way (except when it is there to block the way, purposefully), there is no confusion, no 'where do I go now?' (except for this one roof level where there were a few stairs I didn't see). Anyway, to sum it up: I played through the game in a technical day. I still love the game. I wrote this a couple of years ago but didn't get around to post it, I've just polished it up and am doing so now.
Aaand I think I'm getting in the mood for some Oni once again...