Please note that under most circumstances, I would not openly advocate for "grinding" in a competitive multiplayer game. Experience is supposed to show the differences between higher skill veterans and fresh meat, sometimes through visual differences or even through weapon choices. However, Interstellar Marines has little to no activity in both Multiplayer or Co-Op, and Wargames is so vast that even when fully populated it isn't that effective for ranking up. The following guide is meant for achievement hunters who really want every achievement, including the rank ones, or players like myself who would enjoy having access to one of the higher level skins. I do not claim this guide will actually make you a better player, only that it will help players who are currently struggling to rank up.

It is obvious why you clicked this guide. There's no shame in it, Interstellar Marines has little activity, even on the weekends. Many players might have a hard time finding any full servers to go rank up in, and even then they might be subject to a stomping by higher leveled players. If all you care about is leveling up your rank, and want a quick way to do so, look no further.

Firstly, load up the SCENARIO (meaning single-player) Nucleus Escape A. You can do it on co-op as well if you really want to, however the most efficient method is to do it by yourself. Make sure to select Easy as your difficulty, as it is the only difficulty with infinite lives, and this is actually more important than you would think.

Go through the level as normal. It is fairly straightforward, so I shouldn't have to guide you on that aspect at all. All you need to know is that once you reach the elevator, this is where the grinding will begin.

If you have ever played the "Get Killed by Bots" playground scenario, then this arena will look and feel very familiar. That is because it literally is the same exact scenario pasted into the very last part of Nucleus Escape. Once you reach this area, you will have a checkpoint right at where you begin this part, meaning if you die you will simply respawn at the beginning of the ARENA, and not the level. (This is important, we all make mistakes and it's a big waste of time having to go through the level all over again.)

Originally, CTRs would only give 5 TP when you eliminated them. This made it very inefficient to grind CTRs. Also, the "Get Killed by Bots" scenario doesn't give TP, however, normal single-player scenarios do, including this last segment of Nucleus Escape. It should also be noted that, sometime in the recent updates, CTRs were bumped to give 10 TP per kill, the same as killing another player(!).

And that's it! Simply run around and kill CTRs to your heart's content. Don't worry about running out, they will constantly spawn around the map in droves. Newer players may have a bit difficulty at first, but you'll get the hang of things. Veteran players will easily mop the floor, and you can rank up extremely quickly in no time. (For reference, I went from TR-61 to TR-71 in an hour of grinding.)

One last important thing. Every ten levels will double the amount of TP needed to rank up. This means that at lower levels, this method of grinding is EXTREMELY quick, but once you hit higher ranks it can slow down. (Though it is still the fastest method short of hacking/boosting with other players, which I personally consider cheating.)

While not necessary to the grinding method, I do want to make clear that sitting in one place staring at a screen is not only mentally unchallenging or stimulating, but also unhealthy. If you are taking a while to rank up, or are just playing for a real long time, I would suggest you every ten rank ups (or an hour straight of playtime) to take a break of anywhere from 15-30 minutes. Just go outside and enjoy the weather, or if you can't do that, read a book, draw, write, dance to music, whatever you enjoy doing other than videogames. This keeps both your mind and body fresh, making the process of grinding a bit more bearable than if you just marathon to TR-100. (Which will take 20,000 CTR kills to get to from TR-0, by the way.)