Hi Vertti.
Did you played in the Web Mode.? It seems that the game get sluggish in the MiniMicro Web GL Player (maybe because it's a little big size wise for MiniMicro or a Chrome thing) If you have Windows I recomend you to download and play the game.
About the Tension Meter is actually your (the monster) tension. In design way: It's like you so excited to eat the poor guy that you start to make more "noise" coming at him (MiniMicro don't have a dynamic volume change for sound fxs so put the "sound thing" in your imagination. The main idea of this was the 'little crepy piano in bg getting higher at more tension you have") standing still calm your creature, hiding make it invisible for the guy, but the monster also can't see its prey. It can not get to relaxed
In the mechanic way: More tension = more you make your target gets aware of you per time. Stealth mode release a tiny bit of tension compared to standing still, this is made for the risk v.s reward system of the game, so you cannot abuse being hidden and drops tension to 0 to make you easier to traverse the scenario.
The target awaraness is based on the exclamation mark size and color that appears at his side.
The big tip for you to beat some levels is:
>> Pay atention on how much the exclamation grows after the "huh" (noise cue) and how much tension you have on screen, so you can see how much "huh" cycles your tension level triggers your victim. If tension is too high, stay in stealth wait him to look and reset his awareness, stay still for a few secs so you can get a little extra "huh" cycles.
>> You can time how much the awareness grows in full tension and YOLO your way out and hide only you see its necessary (this tatic made me get to level 5 at best). Higher levels make your tension impact more the victim awareness, so he can insta look at you.
>> Far you get to the level creepier you get and slower your move speed get. So you need to pay extra attention to not try to YOLO too much without calculating your variable velocity. There are 3 forms - each have different move speed, but the back speed its the same in all forms, so in real peril you can go backwards to reset some of your tension (or avoid a spotlight), of course this make you backtrack to your goal. Only go "left" if its your only best choice.