Not a bad game for the adult audience, though I feel it could use some improvement. I will list what I feel it needs, though please do not feel obligated to do any of this, it is just some constructive feedback to consider.
1. A main menu. It just throws you into the gameplay instantly which while I appreciate that straight-to-the-point approach, it could use a menu/logo for the game.
2. An intro cutscene to set up the setting and lore for the main gameplay, perhaps providing names/backstory for the characters involved.
3. High score system with saving. You know, so you can beat your old record. Perhaps adding your score to the screen during gameplay so you can see how many points you have total as you play.
4. Music/sound effects. A warning alarm audio cue when the mom is about to enter, and music for when the mom is not there.
5. More "modes". There are many different positions to consider adding, and ones that could be unlocked after you reach a certain amount of points from other modes. The floor of the level seems very empty, you could add a rug there and have them to a doggy position on the rug or something, or even have them 69 on the couch. It would also be nice to get the "climax" animation of white stuff at the end of each mode bar reaching the end. There could even be a role reversal where the man does the advances on the woman instead.
6. Different unlockable rooms/scenarios. There's the kitchen, and the dining room to name a few that could make for a new setting.
7. Have mom appear from different angles. She only seems to appear from the left side. Appearing from the right side and the bottom would add extra elements to look out for.
8. An ending/set progression. It seems endless until you get caught or close the game. Base progression on unlockable modes within the room and how many points are attained.
9. Unlockable bonuses. For example, coming home with a different girlfriend who has a different character design, same for male, you could even add the ability to unlock a dad mode instead of mom, or have a super difficult mode where both mom and dad have to be avoided (brothers and sisters could also be considered for extra difficulty).
10. Colorization. It would be nice to have.
That is all I can say on this.