Although I won this game by 60.5 points, I already found some obvious mistakes. For instance, Black 190 should have been at P17. Black 204 should have been at R15; giving up the 5 Black stones would have been better and allowed me to save the Black group.

So far those are the only mistakes I was able to find. Perhaps you can point out less obvious ones. Much obliged in advance for your comments.

is a DFK mistake. This has to be at B3, no question.

Don't get shut in! I understand , but isn't joseki, and you now have a problem round here. You must get out to the centre somehow. D12 looks nice, but doesn't work if White knows about "ko lock": i.e. White C12, Black C13, White E13, Black C11, White D11.

Coming out with Black C12 is also bad shape: White plays D12. So Black has to play D13 and see what happens. It looks thin, but Black should survive with the play at D16 in reserve.

at Q3 would be logical.

is a "raw peep": you may want to cut instead. Q9 would be a normal attacking shape.

You won that game, but only by 2,5 points, not by 60,5. It seems you counted the top right as some sort of seki, but black is all dead in top right (w can simply take at o19 to kill it).

The OGS record counts for Black 70 points of territory and 35 White stones captured. For White it counts 32 of territory, 12 prisoners, 0.5 komi and the 2 handicap stones. which for some reason were left out of the final score. The tally is 105 points for Black and 44.5 for White.

I took a second look at the game record and counted the seki area at top right as covering 22 moku on the board. If we include the 14 Black stones in the same area, 36 moku are covered. Elsewhere, White has 33 empty moku, if the potential one at S11 is included, and 21 dead stones, which means 12 points without komi. If the whole top right is counted as White's territory, that's 39 points more, for a final score of 51 points without komi. Black has 69 points and 3 dead stones, which means 66 points. If the 23 Black stones in the top corner are counted as dead, Black has 43 points, excluding any reverse komi.

If it turns out that I lost the game, it was because of Black 190. Otherwise, after this move is played at P17, White blocks at P18 and with Black 192 at R16 the Black group lives. However, at the time I was working on the Black group in the center, so I did not come back to the top right Black group till it was too late.
By "kill" you probably mean "capture". How can you kill what is already dead

You won the game by 2.5. Open the game in an sgf editor and score it properly, and you will see it.