Hi. It's a rather simple concept, but you made sure to (almost) perfect it.
The need to collect hearts (and the 'chaser') forces you to move around. If you're fast, you're also allowed to make a mistake or two. All collisions only decrease the timer and the number of yellow stuff onscreen increases over time (thus the difficulty, too) which means the game doesn't go on forever until you quit out of boredom.
You even managed to sneak in an ad which will serve you well on the mobile platforms, because players will naturally want another chance, especially if they were close to the highscore. There's also background music, light glow and particle effect on impact, and the maze-like background; all of which make it more interesting.
If this is really your first game – wow. Incredible. Even as far as marketing is concerned.
I'll list some problems I noticed.
Since you say you're new to this, I'll also give tips on how to solve it.
– Why is there an alpha slider for colour? You can even hide the UI and the character completely (but interestingly, I did fairly well when it was hidden because there's still light underneath). Oh, and I wouldn't use the default UI sprites (e.g. sliders, buttons…). They look a bit lame and are because they're the default, they're also somewhat overused in Unity games.
– External links (e.g. Twitter) should open in a new tab, otherwise, it will crash the game if you try to open it in the same window.
https://bitbucket.org/newgrounds/newgrounds.io-for-unity-c/src/7862ec579a9e452cb33070df663f2e11fcf02eeb/Assets/io/newgrounds/core.cs#lines-105
https://bitbucket.org/newgrounds/newgrounds.io-for-unity-c/src/7862ec579a9e452cb33070df663f2e11fcf02eeb/Assets/Plugins/WebGL/newgroundsioPlugin.jslib#lines-187
– There's a thin horizontal line at the top of the chaser's sprite sometimes. Sometimes it can happen if the sprite's border is tight and something overlaps, or if you use filtering which might take neighbouring pixels
– The game should be paused when you're browsing the settings. The character still moves underneath, so you can even accidentally start the game when trying to alter settings
If you browse the About page, you can even gain an advantage because the chaser is frozen, so you only have to worry about the yellow droplets
– 'Darkness' is outside of the screen. I'd check the canvas settings and the text's anchor (pivot). Make sure you anchor it to the left screen border, and its pivot is also to the left.
– You seem to be checking if the time is 'less' than zero rather than zero, so when you run out of time, it ends up on '-0.02' (presumably Time.deltaTime in FixedUpdate). It can also go way below zero if you collide with something at the last moment.
Clamp it to zero before assignment (Mathf.Clamp(time, 0, float.PositiveInfinity) and check also for zero, keeping in mind it's a float (Mathf.Approximately(time, 0f)).
– This font is good for titles and short labels, but reading the About page using it is a pain
– When the chaser 'smiles' and doesn't hunt you, you can touch it again to reset its timer harmlessly. A bug? A feature?
If you plan to post more games on Newgrounds, consider using Newgrounds API (https://www.newgrounds.io/) to add medals and scoreboards, which in turn tends to attract more players and makes the in-game achievements and highscores more meaningful.
Good luck with your future games and welcome to Newgrounds!