From: United States
A long time ago someone posted a link on here related to a different puzzle they wanted to see added to your site. I followed that link and discovered a site with a lot of different types of puzzles on it, many of which were similar to puzzles offered here. That site can be found here: https://www.chiark.greenend.org.uk/~sgtatham/puzzles/
The interface on that site is nowhere near as advanced or user friendly as the one Conceptis provides. For example, Conceptis' interface includes the ability to check your current progress, which is a great benefit if you simply want to know whether you've made a mistake without having to see the entire solution. That said, there are many puzzles on that site which Conceptis doesn't have an equivalent of. Some of them would be nice to see added here. Even the puzzles that do have equivalents here sometimes have additional variety there which is missing here. In particular...
On that site, there is a puzzle type named Loopy, which is identical in concept to the Slitherlink puzzles found here. Their version of Slitherlink has options for many different shapes and configurations. Not just a rectangular grid, but triangular, hexagonal and many mixed shape configurations.
Slitherlink, with it's rectangular grid, is a good puzzle. Loopy, with these other configurations, introduces much more variety and requires finding new logic patterns in order to solve them.
I would really love to see you introduce at least some of these as alternate shape Slitherlink puzzles similar to how you have alternate style Sudoku puzzles.
Please consider expanding Slitherlink to include some of these from time to time.