I'll admit, I loved the concept of this game, and even the first few dozen hours as you get around to developing your squad, base, and weapons. It just seemed to hit so many good boxes: tower defense, RTS, looter/extraction shooter FPS, and even roguelite. All those aspects sound like it'd make an incoherent game, but to the extent I played it, it all works out, but it's clear the level of development they put into OIS overall, to help accommodate all those functions, really stretched the game too thin, and made it a chore to play by the later stages.
Speaking from where I stopped playing, I'll say its strongest suits are definitely with the mixed FPS/RTS play when it comes to the meat of combat: extraction day defense. As a looter/extraction shooter, naturally you'll be gathering materials and items on every run across a set of pseudo-predestined stages (hence the roguelite nature). Once you reach the extraction point, you have to defend against hordes of mech units using a combo of innate base defenses (which you pre-build before each expedition), acquired defenses through runs, and your own operator's weapons and kit. This big holdout mission terminating each expedition is where I found the most polish and fun; enemies had decent variety and it was clear you needed to diversify your defenses to milk a relatively clean experience, and it was always fun to grind that part out! From mech suits, launchers, and a ton of turrets, the options were varied and the systems worked well together between overhead RTS and your boots-on-the-ground FPS.
Unfortunately, beyond extractions day defenses and endless defenses, that's where the fun ends and all the tedium and unfinished development really bogs down your enjoyment, at least in my opinion. Story and characters are painfully bad and just cringey with the quality of voicework and the stiffness of the characters. After experiencing a handful of repeated expeditions of each difficulty, learning the common lines in every stage, the in-betweens leading up to extraction day are utterly boring. Enemy variety in these stages is very minimal, and it's painful having to experience each individual stage EVERY time, constantly running short on inventory space when you need so much of everything to develop a well-rounded base and player character/operator (mostly the base). I can tolerate grind, but OIS really overdoes the tedium with it.
Given they announced a sequel is in the works, I suppose we could look at OIS as the first stage of this game's real form. Granted, the asking price for this game is a bit over 20 bucks, so in theory you'd get your money's worth of time in this game, but I just wish they had really stuck with this game and made a polished experience for the final product, because again, seeing what they had so far gives me hope that all these genres of gameplay CAN work well together. It just ain't here.
