Losing interest by the 2nd play through, done by the 4th.

There are only 3 different playable characters, all with very minor differences.

There few weapons and weapon augments so it't not a lot of RNG, its not a "what will i play this round?", its a "when will I get my build?"
You max out on crystals 60% through the run with nothing else to upgrade, with no further upgrades so you just feel weaker and weaker as the run progresses.
Game becomes ridiculously easy after the first 2 runs when you figure out the build which you can just repeat every run.

TL;DR: It's not a bad game, it's just not a particularly great game. Maybe on sale.

Good things first: I like the art style. The setting concept is fun and fits well with a roguelite experience. The character designs are nice, if generic. The core ideas aren't bad. I really liked that the gameplay is set up in 3-5 minute bites. I only ran into one major bug, and it was due to some weird combination of keypad and keyboard buttons being hit at the same time.

Now the bad: It feels wholly inessential. Get guns, strap them onto your mech, upgrade them with pickups, improve your core stats. Get some non-gun upgrades to improve some stats and maybe lower others. Pretty standard Survivors loop.

The problem is that there's just... nothing there.

With two exceptions, I went through four whole runs (one unsuccessful at the beginning, two successful "regular" runs, and one done as fast as I could) and I could not tell you why you should prioritize any stat over another. Pick four random mods per each gun and go; it just doesn't matter. Oh, they might change what the gun does, even in a visible way, but I literally picked random guns on my fourth run and threw random mods in. No difference.

There are four characters in the game, of which it looks like you can currently only unlock three. One says its under development, but who knows if that's accurate. Each character has slightly different stats, a different starting gun (which any character can find in pickups), and a special that sets them apart. The first one has a dash, the next has a big missile attack, the last has a character-centered AoE. That's it.

No "this character does more damage with close combat, that character does more with beams, the third likes fire weapons." Oh, one of them says she really likes explosions, but that's just a way to say "this is their special." Certainly nothing as interesting as "this character carries more guns but gets fewer mods" or "this character gets a bonus for having the same type of gun on multiple slots." Nothing to lead you to build one character different from the next, or at least nothing major.

The missions at first seem like they might have something interesting going on. You have to survive a certain minimum amount of time in a mission before you're allowed to exit, and each mission has two bonus objectives. The bonus objectives are pretty anemic, though: activate one of two different types of helpful structures, which you're already incentivized to do; or destroy X number of some type of enemy, all of which are actively running towards you anyways. There's one that's a little different, killing nests, but you just kind of sit next to them and wait for them to die.

Speaking of waiting for them to die, the bosses are dumb-as-rocks bullet sponges. It's trivial to get the charger stuck on a rock or a light tower and shoot them from behind it. The ranged bosses have a ridiculous windup, so as long as you keep moving, you'll be fine. You can get fast-moving or charging bosses stuck on other bosses, too, so it's possible to literally hide behind your enemies. Even the big boss at the end offers no significant challenge.

There are some interesting ideas here, but none of them gel into an exciting game. I wish they did; I'll be keeping an eye on it as it moves to 1.0. Absent some huge changes, though, I can't see it being worth buying unless you can either get it very cheap, really love mecha, or have exhausted all the A- and B-tier roguelike/survivor games out there.

Punished for not being able to no-life the game

So much of the game balance relies on you on having a high level of progress in the research hub; Without some significant levels in the research (several runs which are right from the get go doomed to fail simply because you don't have good enough upgrades). For example in Nikkes' survivor mode, Para+Bellum, Wings, and lot of other survivor games there is still very much a sense of progress in the early game, A sense of "Pride and Accomplishment" You can still unlock characters pretty quickly, you can still reach the endgame even if you are missing 100x upgrades if you are good enough. This game does not respect your time.