One of Zenwatch's key selling point when it was originally released was its elegant design, so it's just practical for Asus to keep the same form and shape as they create the successor watch.
As great looking as the first "Zenwatch" is, the "Zenwatch 2" is looking more refined than the first one. One big addition to the "Zenwatch 2" is the small metal crown. Also, the "Zenwatch 2" comes with more band options.
Apart from the design differences, here is a quick comparison between the "Zenwatch" predecessor and successor:
"Asus Zenwatch" vs "Asus Zenwatch 2" Body, Display
The first "Zenwatch" measures 2.01 x 1.57 x .37 inches while the "Zenwatch 2" has two variants, one measuring 1.78 x 1.46 x .46 inches and one measuring 1.95 x 1.6 x .43 inches. All three smartwatches are made of stainless steel but only the "Zenwatch 2" watches are IP67 certified to be dust and water resistant, with water resistance of up to 1 meter in 30 minutes. The original "Zenwatch" however, is also not bad with its IP55 certification for its dust and splash resistant body.
As to the screen part, the first "Zenwatch" has a 320 x 320 pixel 1.63 inches screen while the "Zenwatch 2" are available in two variants - one with 1.45 inches screen with 280 x 280 pixel resolution, and one that has a similar screen specs with the first "Zenwatch" which is a 1.63 screen with 320 x 320 pixel resolution. All three said watches are protected by Corning Gorilla Glass 3.
"Asus Zenwatch" vs "Asus Zenwatch 2" Platform
All three devices run Android Wear OS with a Qualcomm Snapdragon 400 chipset, quad core 1.2 GHz Cortex A7 CPU and Adreno 305 GPU. The RAM of the three devices is 512 MB and their internal memory is 4 GB. Only the latter devices are WiFi capable but all three have Bluetooth connection, accelerometer, SMS/Email/IM messaging, MP3 player, and voice/dial commands. The original "Zenwatch" has a non removable Li Ion battery (1.4 Wh) while the newer devices have Li Ion 300 mAh and 400 mAh batteries.
"Asus Zenwatch" vs "Asus Zenwatch 2" Price
The three watches belong to the same price group of 170 Euro to 200 Euro which clearly suggests that going for the newer models is the best choice. The one year gap between devices allowed the company to develop a more beautiful and improved "Asus Zenwatch", Although the main difference is on the devices' physical appearance, there are a couple of big improvements as well that makes the newer models a better option. The dust and water resistance and Wi Fi connectivity are all important smartwatch features that the "Zenwatch 2" has.