ME1 on higher difficulties is interesting in the fact that everything early in the game is just so disproportionately overpowered, while you end up outranking and one-two shotting people late game with overpowered abilities (marksman, assassination, immunity, etc). Early in the game, enemy squads usually just turn on immunity, walk through your cover and blast your squadmates while you can't even damage race their immunity.
That's because ME1 had a really bad case of exponential character growth. As you advance through the game, the damage that your weapons do via your weapon proficiency skill grows, the damage that your weapons do via inherent weapon stats grows, weapon damage is kind of multiplied by how accurate they are and how long you can fire them versus waiting for them to cool down, and all of
those things advance in parallel with your basic damage. You get
more bonuses to damage through passive skills like your class skill and your Spectre Training.
You start the game with low health, low damage reduction on your armour, low shields, and a single skill that restores about half of your shields and a single skill that restores a small amount of health as your sole defensive ability. As you advance through the game, your health goes up, your armour gets better damage reduction
and stronger shields, your Shield/Health restoration skills become usable more frequently and become much more powerful, you get passive, constant health regeneration,
and you gain further skills that either double/triple your shields
and make them regenerate constantly even under fire, or you get a skill with such a boost to damage reduction that you can literally take rockets to the face without noticing a change in your health bar. And those skills start to refresh so quickly that they're up permanently as long as you can remember to hit the button once in a while.
You start with one or two biotic skills that ragdoll an enemy for a second or two, or a tech skill that disables their guns for a few seconds, and those skills take nearly a full
minute to recharge. You get more skills (three or four, at least), all of those skills grow to disable the enemy for longer periods of time, to have larger areas of effect so that more enemies are affected per skill,
and the cooldown on individual skills just gets lower and lower until it's more of a hassle than it's worth to even bother using them as their cooldowns come up.
When you have that many factors that play into how powerful you are, and they're
all going up in parallel, at the exact same time, you end up with this really bizarre difficulty curve where a single enemy is a juggernaut that tears through you like tissue paper for the first couple hours of the game, and you slowly,
sloooooowwwly get stronger, little by little, until you finally don'tfeellikeachumpnow
thegame'sdifficultyisalrightbut oh no there it goes, now I'm one-shotting everything and I'm invincible. The window where Mass Effect 1 actually feels like you're an appropriate level of strength to be fighting the enemies you're put up against is hilariously small. Like maybe levels, I dunno... 18 to 23, or some shit, out of a full spectrum of 1 to 60.