Gave the first 2(?) levels a try. I like where this game is going. Very impressed with the polish so far. I do have some gripes about it, though. I'm mostly familiar with the megaman games, since I've been a rabid fan of them since I was a teenager, so most of my comparison will come from those.
I'll start with the CONS:
CONS:
1) The most noticeable difference I noticed between this and other games of the genre series is that I have no air-control. The character in ECHO cannot change directions or move while in midair (AFAICT), which makes the controls sluggish and projectiles difficult to dodge. Makes jumping over enemies more difficult than if this was in Megaman or Metroid. I'm not sure if this is due to a limitation of the Doom engine or a intended set up.
2) The dash needs a buff. It barely pushes the player 6 inches and is almost never useful from what I've see so far. It's probably faster to just run. The only time its useful is when I dash jump, and that has limited use because of the lack of air-control.
3) The normal plasma gun seems to have a lower DPS than the out-of-charge plasma gun. And the fully charged plasma gun does too little damage to be worth spending the entire energy meter. Maybe make it shoot thru enemies or something.
4) This might be impossible in the Doom engine but is it possible to make the Up key the activate key, and allow the player to lower them selves from a higher platform by pressing down?
5) Enemies movement and attacks are a bit too fast for this sort of game. Combine with the sluggish controls, it makes ti very hard to dodge things compared to other games of the genre.
6) Auto-saves could use some work. Let's just take the first level. If I die after activated the power, even if I got to the giant ramming bugs, I restart to before I turned on the power have had to run that fire gauntlet all over again. Assuming that was a mid-boss, the autosave should be moved to where I enter the room, not way back to the reactor.
7) The first boss was incredibly hard. Especially for a first level one. There is almost no time to dodge its attack, and they all do \massive amounts of damage.
PROS:
1) Fantastic art style. The sprites and animations are superb, and the environments are pretty sweet. The enemies are especially nice with their fluid animations.
2) Music is very good.
3) Sound design is excellent. Powerful weapon and effects.
4) Lots of potential in this.
Keep up the fine work! I will report any bugs I find after I have more time to play.
