A dull, irritating experience that could have been great with better execution.
The idea of an h-game that's a top-down shooter is a clear winner in my books; Give us some big-ass guns, drop us in with some monsters, and let the carnage begin. Tentacles Invasion, though, somehow manages to fuck this formula up to degrees I didn't think was possible.
First off, the gameplay loop gets repetitive really quick. You run around a map, play zone control to open locked doors or turn on the power (so you can in turn open the locked doors), blast a big pile of tentacles, then rescue some chick you know nothing about before returning to home base. Rinse and repeat this process eight more times, all while being attacked by enemies that spawn on top of you. The luster wears off fast since there's no new gameplay mechanics to keep things fun and exciting. Floor two introduces a few panels that you can't walk across without taking damage and this stupid-ass space pod section that controls like dookie. If you've ever played Earthworm Jim, it's like the tube races in the water level but ten times worse. Oh, and there's a unique game over you get for saving some scientist the game tells you not to save. Yippee.
Side tangent: If we know this bitch is the person who let all these stupid tentacles run amok in the first place and she's by herself in some space pod, why can't I just pull up, put a cap in her ass, and continue on my way? She gets labeled as dead if you don't save her, so why not do the job yourself and guarantee she won't cause any more fuckery later on. I guess the MC is too much of a pussy to do that, even knowing that her sister is getting endlessly dicked down by a bunch of tentacle monster because of this fucknugget.
Weapons, which should be a strong suit for this type of game, are also a big disappointment. You get a standard rifle by default, which has limited ammo. Yeah, your starter weapon has a limited amount of fucking shots before you can't even defend yourself. Ammunition drops randomly pop on the screen when you're not at max rounds, so why couldn't they just give the damn rifle unlimited ammo? It's even more of an shitshow in boss fights where, if your coffers go dry, you gotta run around the screen like an asshole while waiting for another magazine to magically pop up. I've got a high-tech plasma rifle as a starting weapon and you're telling me it runs on standard bullets? Fuck off.
You can also find special weapons that come in the form of bullets dealing increased damage and a flamethrower. That's it. No shotguns, miniguns, spread guns, rocket launchers, lasers, nothing. The flamethrower is also just a more powerful version of the rifle, which is kind of understandable but still lame. The bigger issue is that special guns don't respawn when you venture back out into the breach; Once you pick it up, it's gone for the rest of the game. So if you're like me and grab the items when you first see them because why would you not, you're essentially handicapping yourself for when you return later on. I get this is a horror game and they're doing the whole "you need to make careful decisions" schtick, but that all goes out the window when you're continuously being assaulted by enemies that infinitely respawn.
Oh, the fucking enemy spawns. As mentioned earlier, the tentacle piles that make up this game's entire bad-guy roster have a nasty tendency to spawn right within striking distance, leading to many bullshit moments where you get hit by something you can't even react to. The game tries to patch this over by having destructible armor before the tentacles start eating away at your health, but it feels more like putting a bandage on a bullet wound as opposed to designing good levels with set enemy spawns. Not that it matters much with how the health system works: Once you hit 100% damage, you have a set amount of time to grab a randomly spawning health drop before dying. Unless you accidentally/purposely don't pick up the item, you won't game over no matter how many times you get hit. Again, it feels like more shitty game design to account for the infinite enemy spawns than anything else. Hell, the final area of the game even acknowledges this since you need to run across rooms that deal unavoidable damage (Metal Gear, anyone?).
H-scenes look nice on the surface, but they're all just two second animations on loop. There's only five or six scenes as well, as most get reused multiple times alongside they're accompanying dialogue. Although I'm not a tentacle guy myself, it's disappointing to see the utter lack of originality when the theming at hand gives a wild range of possibilities for lewd content.
The one good thing I can say about Tentacles Invasion is that it's short. That said, I still feel as though I wasted an hour of my life that I'll never get back on this shitload of fuck. If you're in the mood for a top-down shooter, just go and play Shock Troopers instead. Your sanity will thank you.